The Application Of Beauveria Bassiana And Scleroderma Guani In Control Of Monochamus Alternatus And The Distribution Of B.xylophilus In The Pine Trees

Bursaphelenchus xylophilus(Steiner & Buhrer)Nickle was most harmful to Chinese forests at present.Monochamus alternatus Hope was the most important vector of the nematode.To suppress the population of M.alternatus was the key of effective controlling the pine wilt disease.So,we carried out all-round and system research of making use of Beauveria bassiana and Scleroderma guani Xiao et Wu controlling M.alternatus.At the same time,sampling and investigation to the different part of died pine and the stake of died pine had been carried out.By studying the infection experiment of Beauveria bassiana to the overwintering larvae of Monochamus alternatus under different temperatures and dosages,the results showed that:20～25℃was the fittest temperature range for B.bassiana to M.alternatus.Under 20℃,parasitic rates of B.bassiana to M.alternatus by three kinds of concentration of B. bassiana spore suspension were 58%,95%and 100%respectively.By comparing mortality rate of M.alternatus after inoculation of B.bassiana,Scleroderma guani and S. guan with B.bassiana,on the 7th day,the highest death rate of M.alternatus only inoculating B.bassiana was 26.3%;the highest death rate of M.alternatus only inoculating S.guani was 55.0%;and the highest death rate of M.alternatus inoculating and S.guani with B.bassiana was 94.4%.The field experiment showed that the mortality rates of the M. alternatus larvae treated by S.guani with B.bassiana was 61.1%,That of S.guani was 40.8%,And that of B.bassiana was 0.0%.So S.guani with B.bassiana might have better effect to the larvae of M.alternatusThe effect of different reagent or different concentration of the same reagent on B. bassiana,Analysis of variance,the same reagent between different concentration (P=-0.6098＞0.05)and between different reagent,the difference is not notable.Had been made the mensuration of eating condition,life-span of the single or germination infect M.alternatus infected B.bassiana and the oviposition of the female adult.After the single and germination M.alternatus infected B.bassiana,the quantity of their taking food decreased greatly.The result showed that the life-span of the M. alternatus adult which didn't inoculate B.bassiana almost exceeded the life-span of the M. alternatus which inoculated B.bassiana 2 times.It can be seen that B.bassiana can weaken the life-force of the M.alternatus adult greatly and shorten its life cycle.But B. bassiana hadn't distinct influence to the oviposition of M.alternatus female adult. The effect of B.bassiana to the life history of S.guani showed that B.bassiana increased death rate of S.guani greatly and shortened its life life-span.After dealt with S. guani by B.bassiana,the S.guani couldn't oviposit on the surface of the M.alternatus larvae or one or two can oviposit,but can not hatch.In June and July,the distributing of the B.xylophilus in the different location of dead pine showed that the quantity of B.xylophilus in the dead pine had great relativity with the region.The changing order of the quantity of B.xylophilus with the region was Dai hill＞Qianma hill＞Xu hill＞Jing hill.In the same region,from twice pine sampling from Dai hill in the middle ten days of a month in June and the first ten days of a month in July can found that the distinction of the quantity of B.xylophilus was not evidence.Afer the pine died,the B.xylophilus would shift from the base toward the top.By contrasting the investigation of the pine stake of 4 seasons and the sampling from stake,found the oviposition M.alternatus adult and the eclosion of M.alternatus larvae was almost in June and July.But the invading times of M.alternatus larvae would continue to October and November.The changing order of the proportion of the sample quantity which had B.xylophilus with season was Winter＞Spring＞Summer＞Autumn.The changing order of the proportion of the quantity of B.xylophilus in the sample with season was Spring＞Winter＞Autumn＞Summer.From the separating result of twice duplicate sampling from Xu hill and Qianma hill in Autumn and Summer,found that the variety and the quantity of wireworm hadn't great change,but there was not B.xylophilus exist.